Technical Field of the Invention
The present invention relates to a method and apparatus for performing appearance inspection of an object on the basis of an image of the object optically picked up by a camera.
Related Art
According to a system of this sort based on conventional art, whether the appearance of a workpiece as an inspection object is non-defective or defective is determined by picking up an image of the inspection object with a CCD (charge-coupled device) camera and by comparing degree of defect of a small area to be targeted of the inspection object with a reference value (see Patent Literature JP-A-2004-061310).
The system disclosed in PLT JP-A-2004-061310 uses a light emitting diode for a specified wavelength as a light source and also uses a filter which is mounted to the camera to cut light having a wavelength other than the specified wavelength to thereby prevent entry of disturbance light. In this way, in order to prevent entry of disturbance light in the conventional art, the light source is limited and a filter is required to be mounted to the camera.